Morpho-Physiological and Biochemical Responses of Maize Hybrids under Recurrent Water Stress at Early Vegetative Stage

Abstract

Rapid climate change may put future food security under threat, which emphasizes the significance of assessing the morpho-physiological and biochemical traits associated with maize tolerance against recurrent water stress at the early vegetative stage. Three maize varieties (V1, SUWAN2301; V2, SUWAN4452; and V3, S7328) and three water levels (I1, daily watering as the control; I2, watering every two days as the short stress; and I3, watering every four days as the prolonged stress) were employed in a factorial design pot experiment. During the experiment, I1’s soil moisture content (SMC) was maintained at almost 100% of its field capacity (FC), whereas I2 and I3’s volumetric SMC dropped to an average of 22.10% and 11.57%, respectively, following a stress phase. Fourteen distinct characteristics of maize were investigated at 5, 9, and 13 days after watering treatment initiation (DAWTI). The findings revealed that water levels significantly influenced all the tested traits (p < 0.05), except for a few traits at 5 or 9 DAWTI only, whereas the maize variety significantly influenced most of the studied attributes (p < 0.05). Except for proline content in leaf (PrL) and root (PrR); total soluble sugar in leaf (TSSL) and root (TSSR); and root length to shoot length ratio (RL:SL), the value of all analyzed characters was higher under I1 compared to I2 and I3. However, during the first recovery period (RP), the recovery rate (RR) of stem perimeter (SP), root length (RL), root dry weight (RDW), leaf water potential (LWP), leaf greenness (LG), and TSSL were higher in I2, whereas leaf area (LA) and RL:SL was higher in I3. However, in the second RP, the RR of plant height (PH), SP, RL, LWP, LG, and TSSL were higher in I3, whereas LA, RDW, RL:SL, PrL, PrR, and TSSR were higher in I2 compared to each other. Under I3, the RR of biochemical traits, i.e., PrL (29.45%) and TSSR (20.23%), were higher in the first RP, and PrR (20.74%) and TSSL (15.22%) were higher in the second RP. However, the variety V1 could recover more after a re-watering, and, in the second RP, it performed better in the case of LA (120.14%), PH (18.41%), SP (19.94%), RL (17.74%), Shoot dry weight (SDW) (56.82%), RDW (11.97%), LG (0.05%), PrR (42.55%), TSSL (18.54%), and TSSR (22.87%) than other varieties. The maize varieties performed differently under I1 and I3 according to the principal component analysis and stress tolerance index. The variety V1 exhibited superior performance under both water levels. The biplot analysis highlighted the importance of traits, such as PrL, RL, TSSL, TSSR, PrR, and RL:SL, in water-stressed conditions. However, re-watering following a water stress period triggered the recovery rates in most traits, particularly after the second four-day stress period, and variety V1 performed better as well. Nonetheless, more research on a genomic and molecular level is required to gain a deeper understanding of the precise processes of drought tolerance in maize, particularly under recurring water stress circumstances.

Efforts to Stimulate Morpho-Physio-Biochemical Traits of Maize for Efficient Production under Drought Stress in Tropics Field

“…Water stress reduced the relative growth rate of maize considerably, which was consistent with prior research [37,108,109]. Though water stress hampers the maize plant RGR, ethephon treatment might mitigate this reduction, as indicated by the current experiment.…”

“…But in the present study, it was found that the RSR was lower in the water-stressed plot, and this might have been due to higher recovery after re-watering followed by water stress. Kumdee et al [37] also reported that rewatering after a water stress period enhanced the plant's recovery rate more than a non-stressed plant. On the other hand, ethephon can help to maintain more chlorophyl in maize leaves through the promotion of water and nutrient uptake by enhancing root growth.…”

“…Inadequate accessible soil water affects the maize's metabolic activity, biomass deposits, and photosynthetic rate by reducing the chlorophyll content in the leaves, subsequently leading to a drop in the maize yield [32][33][34][35][36]. Several studies revealed that proline, the total soluble sugar, root/shoot ratio, relative water contents, etc., are important considerations for the water stress tolerance of maize [37][38][39][40][41][42].…”

Potentiality of Sustainable Maize Production under Rainfed Conditions in the Tropics by Triggering Agro-Physio-Biochemical Traits Ascertained from a Greenhouse

“…Under long-term water stress, the proline and total soluble sugar content were increased, and it was prominent in G1. In accordance with several studies, proline, total soluble sugar, relative water levels, and other factors are crucial for determining how well maize withstands water stress [45][46][47][48][49].…”

“…The amount of yield loss also depends on the length and intensity of the water stress as well as the phenological stage of the crop that is impacted [41][42][43][44]. In accordance with several studies, proline, total soluble sugar, root-shoot ratio, relative water levels, and other factors are crucial for determining how well maize withstands water stress [45][46][47][48][49]. But these may vary under different environments, in the tropical and temperate regions, which need to be verified.…”